Abstract
Humans use emotions to decipher complex cascades of internal events. However, which mechanisms link behavioral descriptions of affective states to brain activity is unclear, as evidence supports either local or distributed processing. A biologically favorable alternative is provided by the notion of gradients, which postulates the isomorphism between stimulus features and cortical distance. Here, we used fMRI activity evoked by an emotionally charged movie and continuous ratings of the perceived emotion intensity, to reveal the topographical organization of affective states. Right TPJ activity is explained by orthogonal and spatially overlapping gradients encoding the polarity, complexity and intensity of emotional experiences. The peculiar arrangement of this three-dimensional functional space allows the brain to map a wide gamut of affective states. As this organization resembles the coding of psychophysical properties in sensory regions (i.e., retinotopy in V1), we propose emotionotopy as the underlying principle of emotion perception in TPJ.